THE SOLUBILITIES, APPARENT DISSOCIATION CONSTANTS, AND THERMODYNAMIC DATA OF THE DIHALOGENATED TYROSINE COMPOUNDS

1. The solubilities and differential heats of solution of d-tyrosine, dl-tyrosine, diiodo-dl-tyrosine, dibromo-l-tyrosine (hydrated), dibromo-l-tyrosine (anhydrous), and dichloro-l-tyrosine (hydrated) have been determined. 2. Evidence has been advanced that dl-tyrosine is a compound. 3. From the solubility determinations at various acidities, the apparent acid and basic dissociation constants of dibromo-l-tyrosine and dichloro-l-tyrosine have been determined at 25° and 40°C. From these data the apparent heats of ionization have been calculated. 4. The question concerning which of the groups in l-tyrosine and its dihalogenated substitution products is responsible for each dissociation constant has been discussed.